1. Field of the Invention
The present invention relates to a system and method for enabling a node, such as a mobile user terminal, in a wireless communications network to route data packets to other nodes in the network based on the information contained in the data packets. More particularly, the present invention relates to a system and method for enabling a node in an ad-hoc packet-switched communications network to examine the contents of data packets to be transmitted by the node, and to designate a routing path including other nodes in the network via which the data packets are routed to a destination node based on the type of data contained in the data packets, to thus meet desired security parameters or packet delivery quality of service (QOS) parameters, such as low bit error rate (BER) or low latency, most suitable for the type of data contained in the data packets.
2. Description of the Related Art
In recent years, a type of mobile communications network known as an xe2x80x9cad-hocxe2x80x9d network has been developed for use by the military. In this type of network, each user terminal (hereinafter xe2x80x9cmobile nodexe2x80x9d) is capable of operating as a base station or router for the other mobile nodes, thus eliminating the need for a fixed infrastructure of base stations. Accordingly, data packets being sent from a source mobile node to a destination mobile node are typically routed through a number of intermediate mobile nodes before reaching the destination mobile node. Details of an ad-hoc network are set forth in U.S. Pat. No. 5,943,322 to Mayor, the entire content of which is incorporated herein by reference.
More sophisticated ad-hoc networks are also being developed which, in addition to enabling mobile nodes to communicate with each other as in a conventional ad-hoc network, further enable the mobile nodes to access a fixed network and thus communicate with other types of user terminals, such as those on the public switched telephone network (PSTN) and on other networks such as the Internet. Details of these types of ad-hoc networks are described in U.S. patent application Ser. No. 09/897,790 entitled xe2x80x9cAd Hoc Peer-to-Peer Mobile Radio Access System Interfaced to the PSTN and Cellular Networksxe2x80x9d, filed on Jun. 29, 2001, in U.S. patent application Ser. No. 09/815,157 entitled xe2x80x9cTime Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channelxe2x80x9d, filed on Mar. 22, 2001, and in U.S. patent application Ser. No. 09/815,164 entitled xe2x80x9cPrioritized-Routing for an Ad-Hoc, Peer-to-Peer, Mobile Radio Access Systemxe2x80x9d, filed on Mar. 22, 2001, the entire content of each of said patent applications being incorporated herein by reference.
In these types of ad-hoc networks, the algorithms that are used to determine the path of intermediate nodes via which the data packets are routed between source and destination nodes are typically based on the shortest distance between the source and destination nodes or, assuming that the data packet transport medium is wireless, the least power required to perform the routing. However, such algorithms do not necessarily produce a predictable delivery of data packets. For example, routing of data packets can be delayed due to congestion in intermediate nodes. Also, delivery failure of data packets can occur on noisy radio links between nodes.
Accordingly, a need exists for a system and method for improving the manner in which data packets are delivered between nodes in an ad-hoc communications network.
An object of the present invention is to provide a system and method for improving the manner in which data packets are delivered between nodes in an ad-hoc communications network.
Another object of the present invention is to provide a system and method for enabling a node, such as a mobile user terminal, in a wireless communications network to route data packets to other nodes in the network based on the information contained in the data packets.
A further object of the present invention it to provide a system and method for achieving the most suitable routing path for the type of data contained in the data packets by enabling a node in an ad-hoc packet-switched communications network to designate a routing path based on desired security parameters or QOS parameters, such as low BER or low latency.
These and other objects are substantially achieved by providing a system and method employing a node, adapted for use in a wireless communications network, which comprises a controller that is adapted to examine a content of a data packet addressed to a destination node, that can have an Internet protocol (IP) address to which the data packet is addressed. Based on the content of the data packet, the controller selects a routing path including at least one of a plurality of other nodes in the network via which the data packet is to be routed to the destination node. The controller can compare the content of the data packet to routing information stored in a memory, and select the routing path based on the comparison. The routing information can include routing information pertaining to an ability of at least one of the nodes to route said data packet to another one of the nodes in the network. Specifically, when the controller determines that the content includes data requiring low latency, such as voice data, the controller selects as the routing path a routing path via which the data packet is deliverable from the node to the destination node in a period of time which is less than a predetermined duration of time. When the controller determines that the content includes data requiring low BER, such as video data, the controller selects as the routing path a routing path via which the data packet is deliverable from the node to the destination node with a bit error rate less than a predetermined bit error rate. However, when the controller determines that the content includes data suitable for best effort routing, such as certain types of bulk file transfer data, the controller selects as the routing path substantially any available routing path via which the data packet is deliverable from the node to the destination node. The node can further include a transceiver which is controllable by the controller to transmit the data packet to the at least one node in the selected routing path. Also, the nodes along the routing path can examine the contents of the data packets and change the routing as necessary to compensate for changes in conditions along the routing path, such as the unavailability of one or more nodes along the routing path or a change in the characteristics of the link between certain nodes, to maintain desired security parameters or QOS parameters for the type of data in the data packets.